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IMO CONSULTING <br />GROUP <br />Table 2: Proposed Conditions <br />(Peak Flow and Runoff Volume Results - Entire Drainage Area) <br />1-YEAR <br />Peak Flow (CFS) <br />Runoff Volume (AC -FT) <br />Runoff Volume (Gal.) <br />Filtration Level <br />3.3 <br />0.9 <br />28,665 <br />100% <br />10-YEAR <br />Peak Flow (CFS) <br />Runoff Volume (AC -FT) <br />Runoff Volume (Gal.) <br />Filtration Level <br />6.8 <br />0.3 <br />94,214 <br />100% <br />100-YEAR <br />Peak Flow (CFS) <br />Runoff Volume (AC -FT) <br />Runoff Volume (Gal.) <br />Filtration Level <br />14.9 <br />0.69 <br />225,479 <br />96% <br />Minimal Impact Design Standards (MIDS) Calculator <br />1. In addition to the H&H analysis performed, the proposed stormwater BMPs were <br />analyzed using the MIDS Calculator, which is distributed by the Minnesotan <br />Pollution Control Agency (MPCA). MIDS Calculator models site conditions and <br />the affect that BMPs will have. It quantifies BMP attenuation and pollutants <br />removal. <br />2. For those areas of the site where BMPs are proposed, the BMPs will be nearly <br />100% effective at controlling the volume and pollutant loads prescribed by the <br />MPCA, which accounts for the first 1.1 inches of rainfall, which is a more <br />restrictive standard than that of MCWD (1 inch). <br />C. CONCLUSIONS/RECCOMENDATIONS <br />1. The proposed site improvements significantly reduce the outflow rates, <br />volumes, and pollutants from the site. <br />2. The proposed BMPs allow the site to exceed the standards of both MCWD and <br />the MPCA. <br />3. Overall, the North Arm Public Lake Access will be more accessible to more <br />groups of people and provide a wider array of services. Site impacts will be <br />reduced, which will improve the water quality of Lake Minnetonka. <br />4. As part of the project design, a new maintenance plan will be part of the final <br />documents. That plane includes routine sweeping of the lot, removal of <br />sediment from the permeable pavers, and other maintenance activities based <br />on the final products installed in the project and is intended to extend the <br />service life of the components. <br />Should you have any questions or concerns regarding this report, please contact us at your <br />convenience. <br />Sincerely, <br />David J, Ju iff, N), LEED AP <br />IMO Consulting Group <br />I <br />Ismael M tinez-Ortiz, resident <br />IMO Consulting Group <br />North Arm <br />Stormwater Management <br />4 <br />115 <br />